package com.ant.liao;

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.util.Log;

import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

/**
 * @author liao
 * @hide
 */
public class GifDecoder extends Thread {

    /**
     * 状态：正在解码中
     */
    public static final int STATUS_PARSING = 0;
    /**
     * 状态：图片格式错误
     */
    public static final int STATUS_FORMAT_ERROR = 1;
    /**
     * 状态：打开失败
     */
    public static final int STATUS_OPEN_ERROR = 2;
    /**
     * 状态：解码成功
     */
    public static final int STATUS_FINISH = -1;

    public boolean isDestroy = false;

    private InputStream in;
    private InputStream backUpIn;
    private int status;

    public int width; // full image width
    public int height; // full image height
    private boolean gctFlag; // global color table used
    private int gctSize; // size of global color table
    private int loopCount = 1; // iterations; 0 = repeat forever

    private int[] gct; // global color table
    private int[] lct; // local color table
    private int[] act; // active color table

    private int bgIndex; // background color index
    private int bgColor; // background color
    private int lastBgColor; // previous bg color
    private int pixelAspect; // pixel aspect ratio

    private boolean lctFlag; // local color table flag
    private boolean interlace; // interlace flag
    private int lctSize; // local color table size

    private int ix, iy, iw, ih; // current image rectangle
    private int lrx, lry, lrw, lrh;
    private Bitmap image; // current frame
    private Bitmap lastImage; // previous frame

    private byte[] block = new byte[256]; // current data block
    private int blockSize = 0; // block size

    // last graphic control extension info
    private int dispose = 0;
    // 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
    private int lastDispose = 0;
    private boolean transparency = false; // use transparent color
    private int delay = 0; // delay in milliseconds
    private int transIndex; // transparent color index

    private static final int MaxStackSize = 4096;
    // max decoder pixel stack size

    // LZW decoder working arrays
    private short[] prefix;
    private byte[] suffix;
    private byte[] pixelStack;
    private byte[] pixels;

    private int frameCount;

    private static final int MAX_QUEUE = 15;
    private Queue<GifFrame> frameQueue = new ArrayBlockingQueue<GifFrame>(MAX_QUEUE);
    private final ReentrantLock lock = new ReentrantLock();
    private final Condition rCondition = lock.newCondition();
    private final Condition wCondition = lock.newCondition();
    private int icacheParse = 0; // 缓存解码成功的帧数
    private boolean loopParse = false; // 是否已经进入了循环解码
    private ArrayList<GifFrame> frameCache = new ArrayList<GifFrame>(frameCount);
    ; // 当帧数小于MAX_QUEUE时，所有的帧全部缓存
    private int iCurrentFrame = 0;
    private boolean loopCache = false;

    private GifAction action = null;

    private byte[] gifData = null;

    private boolean isLoop = false;

    private int fileType = 0; // 1:resource,2:file,3:byte[],4 stream

    private Resources res = null;
    private int resId = 0;
    private String strFileName = null;

    public GifDecoder(GifAction action) {
        this.action = action;
    }

    public GifDecoder(GifAction action, boolean isLoop) {
        this.action = action;
        this.isLoop = isLoop;
    }

    public void setLoopAnimation() {
        isLoop = true;
    }

    public InputStream getInputStream() {
        return backUpIn;
    }

    public void setGifImage(byte[] data) {
        gifData = data;
        openInputstream();
        fileType = 3;
    }

    public void setGifImage(InputStream is) {
        in = is;
        fileType = 4;
    }

    private void openInputstream() {
        in = new ByteArrayInputStream(gifData);
    }

    public void setGifImage(Resources res, int resId) {
        this.res = res;
        this.resId = resId;
        openResourceFile();
        fileType = 1;
    }

    private void openResourceFile() {
        in = res.openRawResource(resId);
    }

    public void setGifImage(String strFileName) {
        this.strFileName = strFileName;
        fileType = 2;
        openFile();
    }

    private void openFile() {
        try {
            in = new FileInputStream(strFileName);
        } catch (Exception ex) {
            Log.e("open failed", ex.toString());
        }
    }

    public void run() {
        try {
            readStream();
        } catch (Exception ex) {
            Log.e("GifView decode run", ex.toString());
            ex.printStackTrace();
        }
    }

    /**
     * 释放资源
     */
    private void free() {
        if (in != null) {
            try {
                in.close();
            } catch (Exception ex) {
            }
            in = null;
        }
        gifData = null;
        status = 0;
        if (frameCache != null) {
            frameCache.clear();
            frameCache = null;
        }
        if (frameQueue != null) {
            frameQueue.clear();
            frameQueue = null;
        }
    }

    public void destroy() {
        isDestroy = true;
        free();
        action = null;
    }

    /**
     * 当前状态
     *
     * @return
     */
    public int getStatus() {
        return status;
    }

    /**
     * 取总帧 数
     *
     * @return 图片的总帧数
     */
    public int getFrameCount() {
        if (loopParse == false && status != STATUS_FINISH)
            return -1;
        else
            return frameCount;
    }

    /**
     * 取第一帧图片
     *
     * @return
     */
    public Bitmap getImage() {
        return getFrameImage();
    }

    public int getLoopCount() {
        return loopCount;
    }

    private int[] dest = null;

    private void setPixels() {
        try {
            // int[] dest = new int[width * height];
            if (dest == null) {
                dest = new int[width * height];
            }

            // fill in starting image contents based on last image's dispose
            // code

            if (lastDispose > 0) {
                if (lastDispose == 3) {
                    // use image before last
                    int n = frameCount - 2;
                    if (n > 0) {
                        // lastImage = getFrameImage(n - 1);
                    } else {
                        lastImage = null;
                    }
                    lastImage = null;
                }
                if (lastImage != null) {
                    lastImage.getPixels(dest, 0, width, 0, 0, width, height);
                    // copy pixels
                    if (lastDispose == 2) {
                        // fill last image rect area with background color
                        int c = 0;
                        if (!transparency) {
                            c = lastBgColor;
                        }
                        for (int i = 0; i < lrh; i++) {
                            int n1 = (lry + i) * width + lrx;
                            int n2 = n1 + lrw;
                            for (int k = n1; k < n2; k++) {
                                dest[k] = c;
                            }
                        }
                    }
                }
            }

            // copy each source line to the appropriate place in the destination
            int pass = 1;
            int inc = 8;
            int iline = 0;
            for (int i = 0; i < ih; i++) {
                int line = i;
                if (interlace) {
                    if (iline >= ih) {
                        pass++;
                        switch (pass) {
                            case 2:
                                iline = 4;
                                break;
                            case 3:
                                iline = 2;
                                inc = 4;
                                break;
                            case 4:
                                iline = 1;
                                inc = 2;
                        }
                    }
                    line = iline;
                    iline += inc;
                }
                line += iy;
                if (line < height) {
                    int k = line * width;
                    int dx = k + ix; // start of line in dest
                    int dlim = dx + iw; // end of dest line
                    if ((k + width) < dlim) {
                        dlim = k + width; // past dest edge
                    }
                    int sx = i * iw; // start of line in source
                    while (dx < dlim) {
                        // map color and insert in destination
                        int index = ((int) pixels[sx++]) & 0xff;
                        int c = act[index];
                        if (c != 0) {
                            dest[dx] = c;
                        }
                        dx++;
                    }
                }
            }

            image = Bitmap.createBitmap(dest, width, height, Config.ARGB_8888);  //如果你的gif没有透明，且想节省资源，这里可以设置为Config.RGB_565
        } catch (OutOfMemoryError e) {
            e.printStackTrace();
        } catch (StackOverflowError ee) {
            ee.printStackTrace();
        } catch (Exception ex) {
            Log.e("GifView decode setpixel", ex.toString());
        }
    }

    /**
     * 取第几帧的图片
     *
     * @param n 帧数
     * @return 可画的图片，如果没有此帧或者出错，返回null
     */
    public Bitmap getFrameImage() {
        GifFrame frame = getCurrentFrame();
        if (frame == null)
            return null;
        else
            return frame.image;
    }

    /**
     * 取当前帧图片
     *
     * @return 当前帧可画的图片
     * @hide
     */
    public GifFrame getCurrentFrame() {
        GifFrame gif = null;
        if (loopCache && frameQueue.size() == 0) {
            if (iCurrentFrame >= frameCount) {
                iCurrentFrame = 0;
                action.loopEnd();
            }
            gif = frameCache.get(iCurrentFrame);
            iCurrentFrame++;

        } else {
            try {
                lock.lockInterruptibly();
                try {
                    while (loopCache == false && frameQueue.size() == 0) {
                        rCondition.await();
                    }
                    gif = frameQueue.poll();
                    wCondition.signal();
                    iCurrentFrame++;
                    if (loopParse && iCurrentFrame >= frameCount) {
                        action.loopEnd();
                        iCurrentFrame = 0;
                    }
                } catch (Exception ex) {
                    rCondition.signal();
                    return null;
                }
            } catch (Exception ex) {
                return null;
            } finally {
                lock.unlock();
            }
        }
        return gif;
    }

    /**
     * 下一帧，进行本操作后，通过getCurrentFrame得到的是下一帧
     *
     * @return 返回下一帧
     * @hide
     */
    public GifFrame next() {
        return getCurrentFrame();
    }

    private int readStream() {
        init();
        if (in != null) {
            readHeader();
            if (!err()) {
                readContents();
                if (loopParse == false) {
                    if (frameCount < 0) {
                        status = STATUS_FORMAT_ERROR;
                        if (action != null)
                            action.parseReturn(GifAction.RETURN_ERROR);
                    } else {
//						status = STATUS_FINISH;
//						if(action != null)
//						action.parseReturn(GifAction.RETURN_FINISH);
                    }
                }
            } else {
                status = GifAction.RETURN_ERROR;
                if (action != null) action.parseReturn(GifAction.RETURN_ERROR);
            }
            try {
                if (null != in)
                    in.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            in = null;
            checkLoop();
        } else {
            status = STATUS_OPEN_ERROR;
            if (action != null)
                action.parseReturn(GifAction.RETURN_ERROR);
        }
        return status;
    }

    private void checkLoop() {
        if (isLoop) {
            if (loopCache) {
                return;
            }

            if (frameCount <= MAX_QUEUE) {
                // frameCache = new ArrayList<GifFrame>(frameCount);
                try {
                    lock.lockInterruptibly();
                    loopCache = true;
                    status = STATUS_FINISH;
                    if (action != null)
                        action.parseReturn(GifAction.RETURN_FINISH);
                    rCondition.signal();
                } catch (Exception ex) {

                } finally {
                    lock.unlock();
                }
            } else {
                if (frameCache != null)
                    frameCache.clear();
            }
            switch (fileType) {
                case 1: // resource
                    openResourceFile();
                    break;
                case 2:
                    openFile();
                    break;
                case 3:
                    openInputstream();
                    break;
            }
            loopParse = true;
            if (isDestroy == false)
                readStream();
        }
    }

    private void decodeImageData() {
        int NullCode = -1;
        int npix = iw * ih;
        int available, clear, code_mask, code_size, end_of_information, in_code, old_code, bits, code, count, i, datum, data_size, first, top, bi, pi;

        if ((pixels == null) || (pixels.length < npix)) {
            pixels = new byte[npix]; // allocate new pixel array
        }
        if (prefix == null) {
            prefix = new short[MaxStackSize];
        }
        if (suffix == null) {
            suffix = new byte[MaxStackSize];
        }
        if (pixelStack == null) {
            pixelStack = new byte[MaxStackSize + 1];
        }
        // Initialize GIF data stream decoder.
        data_size = read();
        clear = 1 << data_size;
        end_of_information = clear + 1;
        available = clear + 2;
        old_code = NullCode;
        code_size = data_size + 1;
        code_mask = (1 << code_size) - 1;
        for (code = 0; code < clear; code++) {
            prefix[code] = 0;
            suffix[code] = (byte) code;
        }

        // Decode GIF pixel stream.
        datum = bits = count = first = top = pi = bi = 0;
        for (i = 0; i < npix; ) {
            if (top == 0) {
                if (bits < code_size) {
                    // Load bytes until there are enough bits for a code.
                    if (count == 0) {
                        // Read a new data block.
                        count = readBlock();
                        if (count <= 0) {
                            break;
                        }
                        bi = 0;
                    }
                    datum += (((int) block[bi]) & 0xff) << bits;
                    bits += 8;
                    bi++;
                    count--;
                    continue;
                }
                // Get the next code.
                code = datum & code_mask;
                datum >>= code_size;
                bits -= code_size;

                // Interpret the code
                if ((code > available) || (code == end_of_information)) {
                    break;
                }
                if (code == clear) {
                    // Reset decoder.
                    code_size = data_size + 1;
                    code_mask = (1 << code_size) - 1;
                    available = clear + 2;
                    old_code = NullCode;
                    continue;
                }
                if (old_code == NullCode) {
                    pixelStack[top++] = suffix[code];
                    old_code = code;
                    first = code;
                    continue;
                }
                in_code = code;
                if (code == available) {
                    pixelStack[top++] = (byte) first;
                    code = old_code;
                }
                while (code > clear) {
                    pixelStack[top++] = suffix[code];
                    code = prefix[code];
                }
                first = ((int) suffix[code]) & 0xff;
                // Add a new string to the string table,
                if (available >= MaxStackSize) {
                    break;
                }
                pixelStack[top++] = (byte) first;
                prefix[available] = (short) old_code;
                suffix[available] = (byte) first;
                available++;
                if (((available & code_mask) == 0) && (available < MaxStackSize)) {
                    code_size++;
                    code_mask += available;
                }
                old_code = in_code;
            }

            // Pop a pixel off the pixel stack.
            top--;
            pixels[pi++] = pixelStack[top];
            i++;
        }
        for (i = pi; i < npix; i++) {
            pixels[i] = 0; // clear missing pixels
        }
    }

    private boolean err() {
        return status != STATUS_PARSING;
    }

    private void init() {
        status = STATUS_PARSING;
        if (loopParse == false)
            frameCount = 0;
        gct = null;
        lct = null;
        icacheParse = 0;
    }

    private int read() {
        int curByte = 0;
        try {
            curByte = in.read();
        } catch (Exception e) {
            status = STATUS_FORMAT_ERROR;
        }
        return curByte;
    }

    private int readBlock() {
        blockSize = read();
        int n = 0;
        if (blockSize > 0) {
            try {
                int count = 0;
                while (n < blockSize) {
                    count = in.read(block, n, blockSize - n);
                    if (count == -1) {
                        break;
                    }
                    n += count;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            if (n < blockSize) {
                status = STATUS_FORMAT_ERROR;
            }
        }
        return n;
    }

    private int[] tab = new int[256];

    private int[] readColorTable(int ncolors) {
        int nbytes = 3 * ncolors;
        // int[] tab = null;
        byte[] c = new byte[nbytes];
        int n = 0;
        try {
            n = in.read(c);
        } catch (Exception e) {
            e.printStackTrace();
        }
        if (n < nbytes) {
            status = STATUS_FORMAT_ERROR;
        } else {
            // tab = new int[256]; // max size to avoid bounds checks
            int i = 0;
            int j = 0;
            while (i < ncolors) {
                int r = ((int) c[j++]) & 0xff;
                int g = ((int) c[j++]) & 0xff;
                int b = ((int) c[j++]) & 0xff;
                tab[i++] = 0xff000000 | (r << 16) | (g << 8) | b;
            }
        }
        return tab;
    }

    private void readContents() {
        // read GIF file content blocks
        boolean done = false;
        while (!(done || err()) && isDestroy == false) {
            int code = read();
            switch (code) {
                case 0x2C: // image separator
                    readImage();
                    break;
                case 0x21: // extension
                    code = read();
                    switch (code) {
                        case 0xf9: // graphics control extension
                            readGraphicControlExt();
                            break;
                        case 0xff: // application extension
                            readBlock();
                            String app = "";
                            for (int i = 0; i < 11; i++) {
                                app += (char) block[i];
                            }
                            if (app.equals("NETSCAPE2.0")) {
                                readNetscapeExt();
                            } else {
                                skip(); // don't care
                            }
                            break;
                        default: // uninteresting extension
                            skip();
                    }
                    break;
                case 0x3b: // terminator
                    done = true;
                    break;
                case 0x00: // bad byte, but keep going and see what happens
                    break;
                default:
                    status = STATUS_FORMAT_ERROR;
            }
        }
    }

    private void readGraphicControlExt() {
        read(); // block size
        int packed = read(); // packed fields
        dispose = (packed & 0x1c) >> 2; // disposal method
        if (dispose == 0) {
            dispose = 1; // elect to keep old image if discretionary
        }
        transparency = (packed & 1) != 0;
        delay = readShort() * 10; // delay in milliseconds
        if (delay == 0) {
            delay = 100;
        }
        transIndex = read(); // transparent color index
        read(); // block terminator
    }

    private void readHeader() {
        String id = "";
        for (int i = 0; i < 6; i++) {
            id += (char) read();
        }
        if (!id.startsWith("GIF")) {
            status = STATUS_FORMAT_ERROR;
            return;
        }
        readLSD();
        if (gctFlag && !err()) {
            gct = readColorTable(gctSize);
            bgColor = gct[bgIndex];
        }
    }

    private void readImage() {
        ix = readShort(); // (sub)image position & size
        iy = readShort();
        iw = readShort();
        ih = readShort();
        int packed = read();
        lctFlag = (packed & 0x80) != 0; // 1 - local color table flag
        interlace = (packed & 0x40) != 0; // 2 - interlace flag
        // 3 - sort flag
        // 4-5 - reserved
        lctSize = 2 << (packed & 7); // 6-8 - local color table size
        if (lctFlag) {
            lct = readColorTable(lctSize); // read table
            act = lct; // make local table active
        } else {
            act = gct; // make global table active
            if (bgIndex == transIndex) {
                bgColor = 0;
            }
        }
        int save = 0;
        if (transparency) {
            if (act != null && act.length > 0 && act.length > transIndex) {
                save = act[transIndex];
                act[transIndex] = 0; // set transparent color if specified
            }
        }
        if (act == null) {
            status = STATUS_FORMAT_ERROR; // no color table defined
        }
        if (err()) {
            return;
        }
        decodeImageData(); // decode pixel data
        skip();
        if (err()) {
            return;
        }
        if (loopParse == false)
            frameCount++;
        // create new image to receive frame data
        //image = Bitmap.createBitmap(width, height, Config.ARGB_4444);
        // createImage(width, height);
        setPixels(); // transfer pixel data to image

        try {

            lock.lockInterruptibly();
            try {

                while (frameQueue != null && frameQueue.size() >= MAX_QUEUE) {
                    wCondition.await();
                }
                if (frameQueue != null) {
                    GifFrame gif = new GifFrame(image, delay);
                    frameQueue.add(gif);
                    if (loopParse == false) {
                        frameCache.add(gif);
                    }
                    rCondition.signal();
                    if (loopParse == false && icacheParse >= 0) {
                        icacheParse++;
                        if (icacheParse >= MAX_QUEUE) {
                            // 只在第一轮解码，且缓存已经满时，才发这个事件
                            action.parseReturn(GifAction.RETURN_CACHE_FINISH);
                            icacheParse = -1;
                        } else if (icacheParse == 1) {
                            // 第一贴成功解码事件
                            action.parseReturn(GifAction.RETURN_FIRST);
                        }
                    }
                }
            } catch (InterruptedException ie) {
                wCondition.signal();
            } finally {
                lock.unlock();
            }

        } catch (Exception ex) {
            ex.printStackTrace();
        }

        if (transparency) {
            act[transIndex] = save;
        }
        resetFrame();

    }

    private void readLSD() {
        // logical screen size
        width = readShort();
        height = readShort();
        // packed fields
        int packed = read();
        gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
        // 2-4 : color resolution
        // 5 : gct sort flag
        gctSize = 2 << (packed & 7); // 6-8 : gct size
        bgIndex = read(); // background color index
        pixelAspect = read(); // pixel aspect ratio
    }

    private void readNetscapeExt() {
        do {
            readBlock();
            if (block[0] == 1) {
                // loop count sub-block
                int b1 = ((int) block[1]) & 0xff;
                int b2 = ((int) block[2]) & 0xff;
                loopCount = (b2 << 8) | b1;
            }
        } while ((blockSize > 0) && !err());
    }

    private int readShort() {
        // read 16-bit value, LSB first
        int s = read();
        int f = read();
        int t = s | (f << 8);
        return t;
        //return read() | (read() << 8);
    }

    private void resetFrame() {
        lastDispose = dispose;
        lrx = ix;
        lry = iy;
        lrw = iw;
        lrh = ih;
        lastImage = image;
        lastBgColor = bgColor;
        dispose = 0;
        transparency = false;
        delay = 0;
        lct = null;
    }

    /**
     * Skips variable length blocks up to and including next zero length block.
     */
    private void skip() {
        do {
            readBlock();
        } while ((blockSize > 0) && !err());
    }
}
